Powertrain systems operate in response to operator requests and other conditions. Such operation includes controlling one or a plurality of control variables, such as a selected transmission gear, engine ON/OFF, and others. Controlling and changing various control variables may be executed to optimize operation, including changing a control variable to reduce power loss, to reduce power consumption, and improve performance. As such, a control variable may change in response to a change in an operating condition, including by way of example an input from the vehicle operator, an input related to external operating conditions, or an input related to operation of the powertrain system.
A change in a control variable, e.g., a change between engine ON and OFF states or a change between fixed transmission gear ratios, may include some hysteresis to minimize state transitions that may lead to operator dissatisfaction and/or affect service life of one or more components such as electric starter motors and the like. However, continued operation within a hysteresis window at a non-optimal state may increase power consumption.